/*
 *  Copyright 2016 Google Inc. All Rights Reserved.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package com.google.android.apps.forscience.whistlepunk.api.scalarinput;

import java.util.HashSet;
import java.util.Set;

/**
 * Keep track of a set of remaining tasks, using unique string id's. When all tasks are completed,
 * call a final Runnable.
 */
public class TaskPool {
  private final Set<String> taskIds = new HashSet<>();
  private Runnable onDone;

  public TaskPool(Runnable onDone, String... moreTaskIds) {
    this.onDone = onDone;
    for (String taskId : moreTaskIds) {
      addTask(taskId);
    }
  }

  public void addTask(String taskId) {
    taskIds.add(taskId);
  }

  public boolean taskDone(String taskId) {
    boolean wasRemoved = taskIds.remove(taskId);
    if (taskIds.isEmpty() && onDone != null) {
      onDone.run();
      onDone = null;
    }
    return wasRemoved;
  }
}
